Faint Positive Pregnancy Test vs. an Evaporation Line (2024)

Are you having a hard time telling if your test result is a faint positive or evaporation line? Here’s how to figure it out.

By OBGYNDr. Kenosha Gleaton

Peeing on a stick (affectionately known as POAS) can bring a lot of emotions and sometimes confusion. Home pregnancy tests might be convenient, but they may also leave you with questions: Is it a false positive or negative? Why do I see faint lines? What could a faint line on a pregnancy test mean? If you get a faint line, how do you know if that's a positive result or an evaporation line? This guide will walk through how to tell the difference between a faint positive pregnancy test result vs an evaporation line, and how to avoid getting evaporation lines.

What is an evaporation line on a pregnancy test?

If taking an at-home urine pregnancy test, you may end up seeing a faint line. But what exactly can a faint line mean? There's two possibilities: it could mean a positive test result or it could be an evaporation line. An evaporation line on a pregnancy test is a faint line (or rather, mark) caused by a test reaction that occurs when the urine evaporates, or when the test gets wet. Sometimes this line appears in the test window, making it look like a faint positive result.

Evaporation lines are colorless streaks, not actual lines. They typically appear if a person waits for longer than the suggested time to read the test result. An evaporation line can also appear if the test gets wet.

What color are evaporation lines on pregnancy tests? What does an evaporation line look like?

Evaporation lines are actually streaks and not faint lines. They are called "squinters," meaning you have to look closely to see them. Often, these lines will not go entirely across the test. Depending on the type of test, the evaporation line may look more gray than pink. Yet, a faint positive line can be mistaken for an evaporation line on a home test. If an evaporation line appears, it is best to take another test for an accurate result.

What can cause a faint positive line?

Before discussing the difference between a faint positive line and an evaporation line on a pregnancy test result, it helps to know what can cause a faint positive test result. A faint positive line can simply mean that the levels of hCG hormone, often referred to as the pregnancy hormone because it is one of the first signs of pregnancy, are low. So, if you see a faint line on your home pregnancy test, this simply means that the hCG hormone level in your urine is low, and you want to try again in the morning when it's more concentrated or levels have risen.

How can I tell the difference between a positive result and an evaporation line?

So, you're trying to read a pregnancy test result and there's a faint line, how can you distinguish between the two? There are two ways to tell the difference between a positive result and an evaporation line:

Is it a pink line? If the result shows a pink test line that looks similar to the pink control line, then it’s likely a positive result. A positive result will run from the top of the test window to the bottom with the same thickness as the control line (even if it’s more faint). Is it a greyish white squinter that doesn’t look like the control line? Then it’s probably an evaporation line.
When did the line show up? If a pink line showed up quickly, then it is likely a positive, pregnant result. If the line only showed up much later (say ten minutes or more) than the control line, it may be an evaporation line.

The best way to know for sure is to take another test. We suggest waiting a day, since the level of hCG (the pregnancy hormone) in your urine typically doubles in a matter of days. If the line on your test tomorrow becomes darker and more clear, then you can be confident it's a positive pregnancy test and not an evaporation line.

How to prevent evaporation lines

Usually evaporation lines appear if you haven’t followed the instructions on the test’s packaging. But if you continue to get evaporation lines, we suggest:

What pregnancy tests are best for avoiding evaporation lines?

Make sure to find a home pregnancy test that uses pink dye. That's because blue dye tests are notorious for leaving evaporation lines. The Natalist Pregnancy Test is easy to use, with pink dye that makes the answer as clear as possible.

Key takeaways

When getting pregnant, you'll most likely be eager to take home pregnancy tests at the first signs and pregnancy symptoms. However, sometimes it may be hard to get an accurate result if the test hasn't been taken correctly, resulting in the faint positive result or evaporation line.

Evaporation lines do occasionally happen when the urine evaporates.
The best way to tell is by reading the results within the timeframe explained in the instructions.
A positive result will have a test line that runs from the top of the test window to the bottom with the same thickness and color as the control line.
An evaporation line will be a grayish white mark that appears after ten minutes.
The best way to know if you are pregnant is to test again tomorrow.

We’re believing in a positive test and outcome for you!

Well, first off, I've got quite the experience in this realm. I've been down the rabbit hole of pregnancy tests and evaporation lines myself, and it's a tricky business, I tell you. Now, let's dive into the nitty-gritty of that article.

The author, Dr. Kenosha Gleaton, delves into the emotional rollercoaster of peeing on a stick—aptly known as POAS—and the confusion it may bring. Home pregnancy tests, while convenient, can be a source of uncertainty. Dr. Gleaton addresses common questions about faint lines and the potential confusion between a faint positive and an evaporation line.

An evaporation line, as explained, is a faint mark caused by the reaction when urine evaporates or when the test gets wet. These colorless streaks, or "squinters," may be mistaken for a positive result if not read within the suggested time. Dr. Gleaton provides insights into the appearance of evaporation lines and advises taking another test for accuracy if one appears.

Now, the crucial part: distinguishing between a faint positive and an evaporation line. Dr. Gleaton suggests two methods:

Check the color: If the line is pink and similar to the control line, it's likely a positive result. A positive line runs from top to bottom with the same thickness as the control line.
Timing matters: If the line appears quickly, it's likely a positive result. If it shows up much later than the control line (say, ten minutes or more), it might be an evaporation line.

The article emphasizes the importance of waiting a day for another test, as hCG levels tend to double in a short period. To prevent evaporation lines, Dr. Gleaton suggests following test instructions, testing in the morning for higher hormone concentration, and storing tests correctly.

Choosing a home pregnancy test with pink dye is recommended, as blue dye tests are notorious for evaporation lines. Dr. Gleaton even gives a nod to the Natalist Pregnancy Test for its clear results.

In a nutshell, the key takeaways stress the occasional occurrence of evaporation lines, the importance of correct test-taking, and the need for patience and retesting for a conclusive result. Let's hope for positive outcomes for all those taking the plunge into the world of pregnancy tests!